silven r



0a. 6, 1936. H SEVEN Re. 20,127

CONTROL MECHANISM FOR GRINDING MACHINES Original Filed Aug. 13, 1934 25heets-Sheet l 3mm v HERBER T A. SJLVEN Oct. 6, 1936. 5|LVEN Re. 20,127

Y CONTROL MECHANISM FOR GRINDING MACHINES Original Filed Aug. 13, 1934 2 Sheets-Shet 2 1fi'm:1

F7113 3mm IHERBEQR T A. SILVEN Reissued Oct. 6, 1936 CONTROL MECHANISM 'FOR GRINDING MACHINES Herbert A. Silven, Worcester, Mass, assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Original No. 2,016,932, dated October 8, 1935,

Serial No. 739,616, August 13, 1934. Application for reissue August 12, 1936, Serial No. 95,699

16 Claims. (Cl. 51-237) The necessity for manually positioning the 5 work requiring the use of a chuck or other work work holder or chuck in a predetermined locaholding means,it has been the practice for the tion for removal of the finish ground piece and operator manually to locate the work holding loading of a new piece has resulted in a' considermember in a given position so that the work able loss of time in the cycle of operation, therepiece may be inserted in operative relation thereby impairing the efliciency of the machine, 10 with. These mechanisms have required the op- It is the primary object of this invention to erator manually to turn the work-holder or chuck provide a work rotation control mechanism which or to jog the control lever to engage the clutch automatically stops the rotation of the work and rotate the chuck to the predetermined loadholder in a predetermined position for loading 5 ing position. Similarly, after the work piece had and unloading. been finish ground, it was the practice for the It is another object of the present invention to operator to jog the control lever again or manprovide a suitable work rotation control mechaually to turn the work holder to locate the work nism which permits stopping either a single head holder in an upright or predetermined loading or a, double head work drive when the work position. holder or .pot chuck is in any predetermined posi- 20 A grinding machine of this type is disclosed tion. in the prior patent to Silven and Belden No. It is a further object of this invention to pro- ,83'7,342 dated December 22, 1931- This 1113- vide a suitable electrical control mechanism chine is particularly adapted and intended for hich stops th k tati n h n th work use in the grin 0 t e et o ankpins 01 a holders are in an upright position. 25 crankshaft. The work piece is placed in position oth object n apparent from the fore. in t pp Work holders or pot chucks, and going disclosure. One embodiment of this inis then ped ri y i Place y a Spring vention has been illustrated in the drawings, tua d to Clamping m ni m which s in which like reference numerals indicate like 30 leased after grinding by means of a fluid presparts-1 sure piston and cylinder on each end of the table. 1 is combined djagranlmatlc fragmen- The op P Chunks are rigidly mounted 0n tary perspective view and electrical wiring diaa pair f pp s d w a n p dl s whi gram, showing the electrical control for are yn hr nously rotated fr a Common drive automatically stopping the rotation of the work shaft below the work supportin t A holder or pot chuck in a predetermined position, 35 ll y p a Control level serves to actuate a the parts being in the position occupied when clutch or the like to start the work rotation when t stop actuation has started; moved into one POSltiOD, 0! when moved into the Fig, 2 1s a, fragmentary longitudinal sectional pp 9051151011 serves to disconnect the clutch view showing work rotation control applied to the and engage a brake immediately and simulwork supporting and rotating mechanism of a 40 taneously to stop the rotation of the work spindouble head erankpin grinding machine; and dles and chucksn Such a mechanism, Drovi- Fig. 3 is an end elevation of one of the work sion maybe ade 80 that the D Chucks Cannot holders or pot chucks for supporting the work, be Op that is the jaws released. to unclamp showing the adjustable cam and limit switch of the work unless the pot chu ks are in n up ight the control mechanism, the parts being in the 45 position. In such machines, in order for the position occupied when they are at rest, chucks to be stopped in an upright position, it Ina grinding machine, such as a double head has been the practice for the operator by expericrankpln grinding machine, the control mechaence to attempt to select the exact moment to nism is, according to the invention, arranged autothrow the manual control lever so as to stop the matically to stop the work holders or pot chucks rotation of the work holders and work piece in in an upright position so that, after the grinding the required position. operation has been completed, the work holders In production grinding, it has been found that or chucks are in a proper position for unclampit is not feasible for the operator readily to stop ing the work without dropping the same from the the chuck in the desired position, and it usually work holder. An electrical control device is pro- 55 This invention relates to grinding machines, and more particularly to a control device for a work gripping and rotating mechanism of a grinding machine.

Heretofore, in the grinding of certain types of has been necessary for the operator to jog the manual control lever to turn the pot chuck through a partial rotation to bring the chuck to the required loading position.

vided to control the work rotating mechanism so that the work holder or support may be stopped in any predetermined position.

A machine illustrating one embodiment of this invention has been shown in the drawings, comprising a base III which carries a wheel slide II on the usual V-way l2 and flat-way |3 for a transverse movement relative to the base It]. A work supporting table I5 is mounted on the usual V-way l6 and a flat-way I'l fora longitudinal movement relative to the base III to position the work piece |8 in operative relation with a rotat-' able grinding wheel l9 on the wheel slide The work supporting table l5 may be moved longitudinally by any suitable traversing mechanism, such as, for example, either a manually operable or a power actuated mechanism. For the sake of simplicity of illustration, a manually operable traverse mechanism has been illustrated, comprising a hand wheel 23 mounted on the outer end of a shaft 2| which is journaled in bearings (not shown) in the base Ill. The shaft 2| carries a gear 22 which meshes with a rack bar 23 depending from the work table l5.

The grinding wheel slide may be fed transversely either toward or from the work piece by means of any well known feeding mechanism, either manual or power actuated, to cause the desired feeding movement of the grinding wheel relative to the work. A manually operable feeding mechanism has been illustrated comprising a feed wheel 25 mounted on the outer end of a shaft 26 which is journaled in bearings (not shown) in the base Ill. The shaft 26 carries at its inner end a gear 21 meshing with a gear 28 on the outer end of a shaft 29. The inner end of the shaft 29 is formed as a feed screw 33 meshing with a nut 3| depending from the wheel slide II. It will be readily apparent from the foregoing disclosure that the grinding wheel l9 may be fed either toward or from the work piece l8 to grind the same to the required extent, or may be separated from the work piece by rotating the manually operable feed wheel 25 in the desired direction.

The work piece may be mounted on any suitable type of work holder, but for the sake of illustration a crankshaft work holder or pot chuck has been illustrated similar to that shown in the prior Patent No, 1,837,342, in which the crankshaft I3 is supported in a work holder 35 which is fixedly mounted on the outer end of a work rotating spindle 36. In grinding a crankshaft, opposed work heads 35 (Fig. 2) are provided, each of which is supported on opposed aligned work rotating spindles 36. prise a partial cylindrical supporting member 31 which is preferably rigidly fixed to the work holder 35 and is adapted to engage and support the end portion 33 of the crankshaft. A clamping jaw 39 is pivotally mounted on the head 35 and is provided with an adjustable clamping pin 43 which is opposed to the supporting member 31. A clamping mechanism is provided for actuating the jaw 39 to clamp and release the work before and after grinding. This mechanism has not been illustrated in detail, since it is illustrated and described in detail in the prior Patent No. 1,837,342, to which reference may be had for details of disclosure.

The spindles 36 are rotated by a transmission train or trains including link chains 45, which engage sprockets 46 one on the end of each spindle 36, and which chain 45 is driven by sprockets 41 mounted on opposite ends of a drive shaft 43 The work holders 35 com-- which is journaled in bearings 49 in the table l5. The shaft 43 is provided with a sprocket 53 which is driven by means of a link chain 5| from a sprocket 52 on a shaft 53. The shaft 53 may be rotated by power from any suitable source, such as from an overhead belt drive or from a selfcontained motor drive within the machine.

In this illustrative embodiment of the invention, a shiftable clutch member 55 is slidably keyed to the shaft 53 and is arranged to be thrown 'towardsthe left (Figs. 1 and 2) into engagement with a positively rotated, power driven clutch member 56 to rotate the shaft 53 and the sprocket 52 so' as to drive the parts above mentioned to rotate the work holders 35. The clutch member 55 is moved toward the right (Figs. 1 and 2) to engage a stationary fixed brake member 53 so as immediately to stop the rotation of the shaft 53 and work holders 35.

The clutch member 55 is arranged to be shifted by a yoked member 63 which is pivotally mounted on a stud 6|. The yoked member is connected by a link 62, a pin 63, an elongated slot 64, and a pin 65 to a rock arm 66. The arm 66 is fixedly mounted on a shaft 61 which is arranged to be rocked by a manually operable control lever 13.

In the position of parts as illustrated in Fig. 1, the, clutch member 55 is in engagement with the brake member 53, and the work spindles are stopping. When it is desired to start the work rotation, the control lever 13 is moved toward the left, as viewed in Fig. 1, so that the lever 13 moves into a notch II in a plate 12. The latter part of this movement shifts the clutch member 55 from engagement with brake member 53 into engagement with the clutch member 56 to start the rotation of the sprocket 52, link chain 5|, sprocket 53, shaft 43, sprockets 41, link chains 45 and sprockets 46 to rotate the work spindles 36 and the work holders 35 positively to rotate the work piece for a grinding operation.

To attain the primary object of this invention, a control mechanism is provided which is so arranged as to stop the rotation of the work holders 35 when they are in an upright or predetermined position, that is, a position in which the work supporting member or surface 31 forms a support for the work even when the clamping jaws 39 are released so as to prevent the work from dropping out of the machine when it is unclamped, and preferably a position convenient for the removal of the work piece and the insertion of an unground one. This control mechanism preferably is electrically controlled and operated and includes an electromagnetic operatingelement such as a solenoid 33 which is connected by a link 8| with the yoked member 63. The solenoid 33 is of the pull type and arranged, when energized, to rock the yoked member 6|) to move the clutch member 55 toward the right, as viewed in Figs. 1 and 2, into engagement with the brake member 53.

In order to energize the solenoid 30 at the proper time, a limit switch 33 is provided in an electrical circuit. Power for the electrical circuit has been illustrated by the power lines 82 which are connected in series with the limit switch 38 and the solenoid 33 so as to energize the solenoid 83 at the desired time. The limit switch 38 may be mounted on the work head 39, and its plunger 99 is arranged in the path of a plunger 9| on a bell crank lever 92 which is pivotally mounted on a stud 93. During the grinding, when the work holders 35 are rotated, the'limit switch 83 is held open. This is accomplished by means of a chain 05 which is connected to the lower end ofanarmiltofbellcrankfl. Thechain05is in turn connected to a bell crank lever 91, the other arm of which is connected by a link 00 with the control lever I0. It will be readily apparent from the disclosure in Fig. 1 that when the control lever 10 is swung toward the left, as viewed in Fig. 1, the bell crank 91 will be rocked in a clockwise direction to move the bell crank 02 also in a clockwise direction so that the pin BI engages the limit switch plunger 00 to hold the limit switch in a normally open position.

A control device is provided to stop the work holder 35 in the desired and predetermined position, namely, a position in which the supporting member 31 will serve as a support for the work piece or crankshaft even when the same has been unclamped. This device may comprise a cam I02 which is adjustably moimted on one of the work heads 35. The cam is provided with elongated slots and clamping screws so that the position of the cam may be adjusted relative to the work holder 35. A cam follower roller I00 is mounted on a stud I09 on an arm H0 of the bell crank lever 92. A spring I03 tends to hold the roller I00 in engagement with cam I02.

Considering now the operation of the mechanism described, the operator first adjusts the position of the cam I02 relative to the work supporting head 35 so that the depression in the cam allows the roller I00 to drop into the position illustrated in Fig. l at a. desired angular position of the parts slightly in advance of the desired stop position. When the roller is in this position, the limit switch 08 closes and thereby energizes solenoid 80. The energizing of solenoid serves to engage the clutch member 55 with the brake member 50 so as to stop the rotation of the work holder in the desired position, such as illustrated in Fig. 3. After the cam I02 has been once adjusted, the cam may be locked in adjusted position so that on successive grinding operations, the work holder is always stopped in the same predetermined or upright position without attention on the part of the operator.

To start the work rotating after loading a new piece of work into the machine, the operator moves the control lever 10 in a counterclockwise direction from the position shown in Fig. 1 into the full line position indicated in Fig. 2. This movement of the control lever 10 serves initially to open the limit switch 8, demagnetizing the solenoid 00. Thereafter, when the pin 55 reaches the end of the slot 60, the clutch member 55 is moved into engagement with power driven clutch member 56.

After the grinding operation has been completed and it is desired to stop the work rotation to permit removal of the finish ground piece of work, the operator moves the control lever 10 in a clockwise direction into the full line position as indicated in Fig. 1. This movement of the control lever serves to move the link 98, bell crank 91, chain 05, to permit the spring I03 to rock the bell crank 92 in a counterclockwise direction so as to bring the follower roll I08 into operative engagement with the cam I02. Due to the lost motion between the pin 55 and elongated slot 50, the movement of lever I0 does not disengage the clutch member. If the follower roller engages the concentric portion of the cam, then the switch 80 remains open and continues to remain open until the head has rotated through a partial rotation into the position illustrated in Fig. 1, in which the roller I08 engages the notched or low portion of the cam I02, thereby closing the limit switch 00 and energizing the solenoid 00, which serves to move the clutch member 55 from engagement with clutch member 56 into engagement with the brake member 50 to stop the rotation of the work holder 35 in a predetermined or upright position.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is: I

1. In a cylindrical grinding machine, a rotatable grinding wheel, a work support, a work holder rotatably mounted thereon, means to support a work piece thereon, means continuously to rotate said work holder to grind the periphery of the work piece, and automatically actuated means to stop said work holder in a predetermined position.

2. In a grinding machine, a work support, a work holder rotatably mounted on said support, means including a clutch continuously to rotate said work holder, and an automatically actuated mechanism actuated in timed relation with said clutch to stop the work holder in a predetermined loading position.

3. In a grinding machine, a work support, a work holder rotatably mounted on said support, a bearing support fixed on said holder for supporting a work piece therein, a clamp associated with said support to clamp a work piece in said holder, means to rotate said work holder, and automatically actuated means to stop the rotation of the work holder when the fixed support on the work holder is in a predetermined position.

4. In a grinding machine, a work support, a work holder rotatably mounted on said support and having a work supporting surface arranged to be loaded and support the work when in an upright position, a clamping member opposed to said supporting surface to clamp the work rigidly on said surface, means including a clutch to rotate said work holder, and automatically actuated means cooperating with said clutch to stop the work rotation when said surface of the work holder is in an upright position.

5. In a grinding machine, a work support, a work holder rotatably mounted on said support, a work supporting surface on said work holder which serves to align and support a work piece thereon, a clamping means on said work holder arranged to clamp the work piece rigidly in said surface, means including a clutch to rotate said work holder, a control cam adjustably mounted on said work holder, and a control device associated with said clutch and cam automatically to stop the rotation of the work holder in a predetermined or upright position.

6. In ,a grinding machine, a work support, a work holder rotatably mounted on said support. a fixed member on said work holder arranged to support and align a work piece thereon, a clamping means to clamp a work piece on said fixed member, means to rotate said work holder, and an electrically actuated cam controlled means automatically to stop the rotation of the work holder in a predetermined position.

'7. In a grinding machine, a work support, a work holder rotatably mounted on said support, a fixed member on said holder arranged to support and align a work piece thereon, a clamping means arranged to clamp a work piece rigidly in said fixed member, means including a clutch to rotate said work holder, and an electrically actuated cam controlled mechanism associated with said clutch automatically to stop the rotation of the work holder in a predetermined position.

8. In a grinding machine, a work support, a work holder rotatably mounted on said support, a fixed member on said work holder to support and align a work piece thereon, a clamping means on said holder arranged to clamp a work piece rigidly in engagement with said fixed member, means including a clutch to rotate said work holder, a manually operable means to engage said clutch to start or to stop the rotation of said work holder, an adjustable cam mounted on said work holder, a control. means associated with said cam and rendered efiective when the manual means is moved into a stopping position automatically to stop the rotation of the work holder when said fixed member is in a vertical or upright position.

9. In a grinding machine, a work support, a work holder rotatably mounted on said support, means including a clutch to rotate said work holder, manually operable means to actuate said clutch to rotate said work holder, a brake associated with said clutch to stop the rotation of the work holder, an adjustable cam mounted on said work holder, and an electrical control device including a switch associated with said cam and a solenoid arranged to move said clutch into engagement with said brake which is rendered effective when the manualmeans is moved to a stopping position automatically to stop the rotation of the work holder in a predetermined position.

10. In a grinding machine, a work support, a work holder rotatably mounted on said support, means including a clutch torotate said work holder, a manually operable means to engage said clutch to start or to stop the rotation of said work holder, a brake associated'with said clutch positively to stop the rotation of the work holder, and an electrically controlled, cam actuated mechanism which is rendered effective to engage the clutch and automatically to engage the brake and to stop the rotation of the work holder in a predetermined position.

11. In a cylindrical grinding machine, a rotatable grinding wheel, a work support, a work holder rotatably mounted thereon, means to support a work piece thereon, means continuously to rotate said work holder to grind the periphery of the work piece, a cam operated by the means continuously to rotate said work holder, a switch operated by said cam, and an electromagnetic brake operated by said switch whereby said work holder is automatically stopped in'a predetermined position in a substantially constant angular distance beyond the point where the cam actuates the switch.

12. In a cylindrical grinding machine, a rotatable grinding wheel, a work support, a workholder rotatably mounted thereon, means to support a work piece in the work holder, a transmission train to rotate said work holder at a constant angular velocity, a cam synchronized with said transmission train, a switch operated by said cam, a source of electric current controlled by said switch, and an electromagnetic brake operated by said source of electric current when said switch is operated automatically to stop said work holder in a predetermined position.

13. In a cylindrical grinding machine, a rotatable grinding wheel, a work support, a pair of aligned work holders rotatably mounted thereon to rotate on acomm'on'axis, a driving element, a

pair of transmission trains one connected to each work holder, a common drive from said driving element to said transmission trains whereby to drive said work holders in synchronism, a cam synchronized with said transmission trains, a switch operated by said cam, and an electromagnetic brake to stop said driving element, whereby automatically to stop said work holders in a predetermined position.

14. In a cylindrical grinding machine, a rotatable grinding wheel, a work support, a work holder rotatably mounted thereon, means to support a work piece in the work holder, a transmission train connected to said work holder, a driving element for said transmission train capable of being operated at a constant angular velocity, a start and stop lever for said driving element, a cam synchronized with said transmission train, an element'conditionally operable by said cam, a connection between the start and stop lever and said element so arranged that when the said lever is moved to stopping position the cam may operate the said element, a switch, a source of electric current, electromagnetic brake means to'bring said driving element to a stop operable by said source when said switch is moved to a stop position, and a connection between the said element and the said switch, whereby after said start and stop lever is moved to a stop position the electromagnetic brake means operates when next the cam reaches a certain angular position thus to stop the work holder in a predetermined position. 7

15. In a cylindrical grinding machine, a rotatable grinding wheel, a work support, a pair of work holders rotatably mounted thereon, means to support a work piece in each work holder, a transmission train connected to each work holder, a driving element for said transmission train capable of being operated at a constant angular velocity, a start and stop lever for said driving element, a cam synchronized with said transmission train, an element conditionally operable by said cam, a connection between the start and stop lever and said element so arranged that when the said lever is moved to stopping position the cam may operate the said element, a switch, a source of electric current, electromagnetic means to bring said driving element to a stop operable by said source when said switch is moved to a stop position, and a connection between the said element and the said switch, whereby after said start and stop lever is moved to a stop position the electromagnetic brake means operates when next the cam reaches a certain angular position thus to stop the work holder in a predetermined position.

16. In a cylindrical grinding machine, a rotatable grinding wheel, a work support, a work holder rotatably mounted thereon, means to hold a work piece in the Work holder, a transmission train connected to'said work holder, a driving element for said transmission train, a manually operable member to stop the work holder from rotation, a control device synchronized with said transmission train, a switch, conductors for electric current, an electromagnetic brake to bring said driving element to a stop operable by said current, and connections between said manually operable member and said switch governed by said control device to apply the electromagnetic brake at a certain angular position of said work holder.

' HERBERT A. SILVEN. 

